1. Field of the Invention
The present invention relates broadly to the field of writing instruments and is more particularly concerned with hand manipulated writing instruments of the type whereby multiple lines are concomitantly applied to a writing surface with each stroke of the instrument.
2. Description of the Prior Art
Over the years many multiple-line drawing and writing instruments have been developed. In one general form of such writing instruments multiple pens are held in fixed array within a housing, the writing tips of the nibs of the pens being positioned in fixed coplanar relationship. Representative of such instruments are the devices disclosed in U.S. Pat. No. 3,164,906, to R.S. Andaloro, entitled "Multiple Pen Combination" and British Patent Specification No. 1,348,135, to W.C. Thomas, published Mar. 13, 1974, entitled "Improved Writing Implement". A problem associated with arrangements where the multiple pens are held in fixed planar array is that such instruments are incapable of adapting themselves to the various writing angles employed by the average population of users. Thus, the user must take care to manipulate such fixed nib devices at the precise writing angle relative to the writing surface at which each pen nib of the fixed array applies its respective ink burden to the writing surface. This manipulative requirement is, at the least, burdensome to the user and usually forecloses direct one-handed manipulation of such devices in the manner of an ordinary single pen or pencil.
Writing instruments adapted for one-, two-handed or machine use and in which accomodation of variations in writing angle can be had either inherently or intentionally have also been proposed. Representative of such instruments are those disclosed in the following U.S. Patent literature: U.S. 425,495, to Demarest, Apr. 15, 1890, entitled "Slate Ruler"; U.S. Pat. No. 1,191,725, to N. Paulsen, July 18, 1916, entitled "Drafting Instrument"; U.S. Pat. No. 1,731,395, to A. Radtke, Oct. 15, 1929, entitled "Instrument for Writing Characters on Advertising Boards"; U.S. Pat. No. 3,405,447, to J. Pfeffer, Oct. 15, 1968, entitled "Drafting Instrument" and U.S. Pat. No. 3,762,054, to A. Ballard, Oct. 2, 1973, entitled "Multi-Line Underlining Instrument". A feature common to each of the instruments disclosed in this patent literature is some form of holder means to retain a plurality of elongate writing means, such as chalks, pen nibs, pencil leads or the like, in parallel, spaced apart array. Furthermore, the holder means utilized in each of these instruments retains the writing means in a manner such that each writing means is imbued with the capacity to stroke upwardly and downwardly relative to both the holder means and to one another. Finally, also common to the instruments described in the above patent literature are biasing means, such as springs, by which each of the writing means of the instrument is independently and continuously urged to the extended stroke condition, that is to say, to the downwardmost stroke position thereof. Said biasing means, of course, serve to maintain each of the plural writing means of the respectively disclosed instruments in continuous writing contact with the writing surface during manipulation of the instrument.
I have found that the biasing means employed in constructions of the type exemplified by the patent literature referenced above represent a substantial complexity in the design, manufacture and assembly of such instruments and, therefore, constitute a significant fraction of the manufacturing costs thereof. Moreover, the overall pressure exerted by said biasing means, particularly with respect to those writing instruments intended to be manipulated by one hand, is necessarily reflected into the hand of the user and can be found to be of sufficient magnitude as to constitute a source of discomfort to the user and/or to adversely affect the accuracy at which the instrument can be manipulated. In accordance with the present invention, however, I have designed an improved multiple line writing instrument for one-handed operation which effectively accomodates variations in the writing angles at which it may be used but which avoids the operational liabilities and the complexities and incremental costs of manufacture associated with those prior art devices which depend upon the presence of biasing means to achieve this functional purpose.